METHOD AND JACKET FOR ENCAPSULATION OF WASTE

Abstract: Method for encapsulation of waste, such as asbestos, iron slag or metal slags, characterized in that said waste, after being broken and/or ground if necessary, is mixed with an encapsulating material which may or not be previously softened or melted, said encapsulating material preferably consisting at least partly of plastic, more specifically plastic waste, where the whole of waste and encapsulating material (22) thus obtained is placed in a hollow vessel (23) consisting essentially of plastic, metal and/or concrete, so as to form a solid mass in this jacket (1), where said vessel (23) is closed so that said whole (22) is isolated from the environment.

Description: Method and jacket for encapsulation of waste This invention concerns a method for encapsulation of waste, such as asbestos, iron or metal slags, residues, ashes, etc. from the metal or other industry. Because of their noxious effects, asbestos waste and/or asbestos fibres have to be processed so that they remain separated from the environment. In order to achieve this, until now the asbestos has been mixed with concrete and then transformed into blocks. These blocks are then stored in a protected environment. However, when such a method is applied, asbestos fibres can nevertheless be released at the surface of these blocks. Such blocks cannot therefore be used as construction material and must consequently be stored in a controlled environment. This requires expensive, long-term storage capacity, which is uneconomic. Furthermore, these blocks maintain their hazardeous effect and continue to pose a certain danger to people. This invention has as its purpose to avoid these disadvantages, by proposing a method which enables the waste material, such as asbestos, to be processed into safe blocks which can be used e.g. as construction material f.i. in the building industry. For this purpose, after being broken and/or ground as necessary, said waste is mixed with an encapsu¬ lation material which may or may not be previously softened or melted, preferably consisting at least partly of plastic, more specifically plastic waste, where the whole thus formed by the waste and encapsulating material is brought in a hollow vessel consisting essentially of plastic, metal and/or concrete, so as to form a solid, more or less coherent mass in said vessel, whereupon said vessel is closed, so that said mass is isolated from the environmen . Solid waste in a divided condition, f.i. fine sized or fine granulated state, can efficiently be mixed with softened or melted thermoplastic material, more specifically, plastic waste, to form a mass which can be formed. This mass is then placed in a jacket, in which it solidifies to form a solid mass. A jacket is used having relatively stiff walls which are heat-resistant at the temperature of said mass and which are impenetrable to it. Means can be advantageously fitted to separate said whole of waste and encapsulating material from said vessel. In a particular embodiment of the invention, said coherent mass of waste and encapsulating material is placed in a mould, with or without said jacket. The remaining space in this mould is further filled with an embedding material, e.g. liquid concrete or molten plastic waste, which then forms the above-mentioned hollow vessel. In a preferred embodiment of the invention, reinforcement is placed round at least part of said jacket. In a further preferred embodiment of the invention, spacers are fitted between the jacket and the mould, enabling said jacket to be placed at a suitable distance from the inner wall of the mould. The invention also concerns a jacket consisting of a container that can be closed, for applying the method according to the invention. Said container can efficiently be partly surrounded by at least one spacer which enables rein- forcement to be placed at a suitable distance from said container. The bottom surface of said container, which is opposite to a surface which forms said lid, can advan- tageously be provided with at least one spacer. According to a particular embodiment of the jacket according to the invention, the surface of said container has said spacer at least partly at the side with respect to the lid. According to a preferred embodiment of the jacket according to the invention, said spacer is removable and U-shaped and encloses said lid at least partly. According to a further preferred embodiment of the jacket according to the invention, the ends of said U-shaped spacer are removably attached to the spacer at said bottom surface. Other characteristics and advantages of the invention will be apparent from the following description of a specific embodiment of the method and jacket for processing waste according to the invention; this description is given by way of example only, and does not limit the scope of the protection proposed; the reference figures used hereunder refer to the attached drawings. Fig. 1 is a schematic, perspective, exploded drawing of the component parts of the jacket according to a specific embodiment of the description. Fig. 2 is a schematic, perspective, exploded drawing of a jacket and a mould, according to a specific embodiment of the invention. Fig. 3 is a schematic, vertical cross-section, to a smaller scale, of a mould with encapsulated waste according to the invention. In the different drawings, the same reference numbers refer to the same parts. In general, the invention concerns a method for processing asbestos waste and other waste materials, e.g. iron or metal slags and all sorts of residues from the metal industry. This waste is preferably mixed as homogeneously as possible with an encapsulating material such as melted or soft plastic waste until it is distrib¬ uted through said plastic waste and a more or less coherent mass is formed. The amount of plastic is preferably 20 to 40 percent of the mixture by weight. If necessary the asbestos or other waste material is first broken up and/or ground to smaller dimensions. This whole of liquid or processed encapsulating material and waste is placed in a jacket where it hardens and forms a solid mass. Such a jacket is shown in fig. 1. The jacket 1 shown here consists of a relatively stiff, heat-resistant plastic and is formed by a cube-shaped container 2, whose open top is closed by a more or less fitting square lid 3. Said lid 3 has at its edge four rectangular openings 4 through which projections 5 pass when the lid 3 closes the container 2. Said projections 5 have holes 6 in the direction of the surface of the lid 3, in which a peg 7 can be tightly inserted which presses the lid 3 onto the container 2, such that the latter is tightly closed. Two parallel, U-shaped spacers 8 are slid over the closed container 2. These then rest on the lid 3 and their legs extend along two opposite side walls 2a and 2b of said container 2. The bottom surface 9 of the container 2 has on the outside two parallel, fixed spacers 10 which are parallel to one of the edges of said bottom surface 9. When the U-shaped spacers 8 are placed over the container 2, they form a closed ring with the spacers 10 on the bottom surface 9 round the jacket 1, said ring being parallel to the side surfaces 2c and 2d of the container 2. The ends of the U-shaped spacers 8 have an opening 11 through which a peg 7 passes into the recess 12 in the ends of the spacer 10, and so fastens the U-shaped spacers 8 to the spacers 10. On each of the side surfaces 2c and 2d of the container 2, which are not enclosed by the U-shaped spacers 8, there are two fixed, parallel, vertical spacers 13. The spacers 8, 10 and 13 have notches 14 in which a reinforcement 15 can be placed, as shown in fig. 2 by the dot-dash line. Said reinforcement 15 can for example consist of a metal mesh or more specifically an iron mesh, as in the embodiment shown, or it may consist of a fibrous material, such as glass fibres or textile fibres, e.g. flax fibres, either in the form of a mesh or as loose particles mixed with the concrete. Once the whole of encapsulating material and waste has been cast in the container 2 and the container has been closed by means of the lid 3 and the U-shaped spacers 8, and once the reinforcement 15 has been fitted, the jacket 1 is placed in a mould 16. This mould 16 is a cube-shaped tub 17 with two supports 18 on each two opposite sides. Said supports 18 project above the tub 17 and have at their top end a concave surface so that a bar 19 rests in equilibrium on two opposite supports 18. The jacket 1 is suspended together with its contents from two steel cables 20. These cables 20 support the bottom surface 9 and extend along the side surfaces 2a and 2b of the container 2, reaching above the jacket 1. The ends of both cables 20 are fitted with rings 21. For each cable 20 there is a bar 19 over which both rings 21 of the cable 20 can be slid. By means of these bars 19, the jacket 1 can be lifted up and placed centrally in the mould 16. For this purpose, each of the bars 19 rests on two supports 18 located opposite each other. Once the jacket 1 has been placed in the mould 16, said mould is further filled with an embedding material 23, more specifically liquid concrete, in which an additive may or not be mixed, enabling a water-tight wall to be formed. In this manner, a hollow vessel 23 is formed which encloses the waste material. The filled mould 16 is shown in fig. 3, containing in the middle the coherent mass of waste and encapsulating material 22, round which is the jacket 1 with the reinforcement 15 which is cast into the concrete 23. The block thus obtained can then be removed from the mould 16 and, once the bars 19 have been removed, can be lifted and transported by means of the rings 21. The waste to be processed is now safely contained, isolated from the environment. If necessary, a recess (not shown) can be made in the top surface of the concrete mass 23 for the rings 21 with the projecting end of the cables 20. This block can for example be used as a construction or foundation block for building ports, dams, dikes or industrial structures, and consists for example of a cube of lm 3 with a centrally cast cube- shaped jacket 1 with a side of 60 cm, so that the wall thickness of the surrounding concrete is 20 cm. This invention is of course in no way limited to the embodiment described above and shown in the accompanying drawings. For example, the jacket 1 can equally well be made of another material, such as steel, and can if desired be removed before the whole of encapsulating material and waste 22 is placed in the concrete 23. The encapsulating material does not necessarily have to be a thermoplastic, but can equally well be concrete, metal or thermosetting plastic. Also, waste materials other than asbestos, for example metal slags, can be processed in such a manner. The jacket 1 can if desired rest within the mould 16 which for example can be made of wood or concrete, and may or may not be removable. Also, the cables 20 can be replaced by chains or bars and/or form part of the jacket 1 or the mould 16. The dimensions and shape of the jacket 1 and of the mould 16 can be of all sorts, and are not limited to the embodiment presented here. The spacers 8, 10 and 13 can for example consist of separate parts, or can form part of the reinforcement 15. The jacket 1 can be formed by a film on the inner wall of the hollow vessel 23, in order to separate the latter from the solid coherent mass of encapsulating material and waste 22. The jacket is preferably inert with respect to said coherent mass, and is impenetrable to the combined components of said mass 22. The hollow vessel 23 can also consist of a separate tub, for example a precast tub of reinforced concrete in which the encapsulated waste, which may or may not be in a jacket, can be placed. In another embodiment, a sealing film may be placed on the inner wall of the concrete tub, instead of a separate jacket. Further, for the purpose of mixing the waste with the encapsulating material, in some cases it may not be necessary to use liquid, molten encapsulating material, but instead it may be sufficient for the latter to be sufficiently softened to form a more or less coherent mass with the waste. For certain waste products and encapsulating materials, it is also possible to use the known sintering technique in order to form a coherent mass. In another embodiment, the mould 16 can be made such that a block is obtained, whose outer wall has projections and corresponding recesses which enable blocks placed next each other to be locked together. Finally, in certain cases the jacket 1 can be used for loose waste which is poured into the container 2. Said container 2 is then closed by a lid 3 and cast into the concrete mass 23 in the manner described above.

Claims: CLAIMS 1. Method for encapsulating waste, such as asbestos, iron slag or metal slags, characterized in that said waste, after being broken and/or ground if necessary, is mixed with an encapsulating material which may or not be previously softened or melted, said encapsulating material preferably consisting at least partly of plastic, more specifically plastic waste, where the whole of waste and encapsulating material (22) thus obtained is placed in a hollow vessel (23) consisting essentially of plastic, metal and/or concrete, so as to form a solid mass in this jacket (1), where said vessel (23) is closed so that said whole (22) is isolated from the environment. 2. Method according to claim 1, characterized in that means (1) are provided to separate said whole of waste and encapsulating material (22) from said vessel (23). 3. Method according to claim 1 or 2, charac- terized in that solid waste in a divided state is mixed with softened or melted thermoplastic material, more specifically plastic waste, so as to obtain a mass which can be formed, after which said mass is placed in a jacket (1) in which it solidifies to form a solid mass, where a jacket (1) is used that has relatively stiff walls which are heat-resistant at the temperature of said liquid mass, and preferably impenetrable to it. 4. Method according to claim 3, characterised in that said whole of waste and encapsulating material (22) is place in a mould (16), either with or without said jacket (1), where the remaining room in said mould (16) is then further filled up with an embedding materiel (23) such as liquid concrete or molten plastic waste, in order to form the above-mentioned hollow vessel. 5. Method according to claim 4, characterized in that reinforcement (15) is fitted at least partly round said jacket (1). 6. Method according to one of claims 4 or 5, characterized in that the jacket (1) and mould (16) are fitted with spacers (8, 10, 13) in order to enable said jacket (1) to be placed at a suitable distance from the inner wall of the mould (16). 7. Jacket (1) consisting of a container (2) which can be closed by a lid (3), characterized in that said container (2) is surrounded at least partly by at least one spacer (8, 10, 13) which enables reinforcement (15) to be fitted at a suitable distance from said container (2). 8. Jacket (1) according to claim 7, charac- terized in that the bottom surface (9) of said container (2), which lies opposite to a surface that forms said lid (3), has at least one external spacer (10). 9. Jacket according to claim 7 or 8, charac¬ terized in that the surface of said container (2) is fitted with said spacer (8, 13) at the side with respect to the lid (3) . 10. Jacket (1) according to any of claims 7 to 9, characterized in that said spacer (8) is removable and is U-shaped and encloses said lid (3) at least partly. 11. Jacket according to claim 10, character¬ ized in that the ends of said U-shaped spacer (8) are removably attached to the spacer (13) on said bottom surface (9) . 12. Jacket according to any of claims 7 to 11, characterized in that projections (5) project from said container (2) which fit more or less in holes (6) provided for that purpose in said lid (3), and which have means (7) to attach the latter to said container (2). 13. Jacket according to claim 12, character- ized in that at least one side spacer (13) has said projections (5) . 14. Jacket according to any of claims 7 to 13, characterized in that said spacer (8, 10, 13) has means (14) for attaching said reinforcement (15). 15. Jacket according to any of claims 7 to 14, characterized in that said spacer (8, 13) extends more or less over the full length of the side walls (2a, 2b, 2c, 2d). 16. Jacket according to any of claims 7 to 15, characterized in that said spacer (8, 10, 13) forms part of said reinforcement (15). 17. Jacket according to any of claims 7 to 16, characterized in that said container (2) is prism-shaped. 18. Jacket according to any of claims 7 to 17, characterized in that said container (2) is bar-shaped. 19. Encapsulated waste, characterized in that it is mixed with thermoplastic to form a more or less coherent mass enclosed by a protective jacket (1). 20. Encapsulated waste according to claim 19, characterized in that it consists essentially of asbestos waste. 21. Encapsulated waste according to claim 20, characterized in that the quantity of asbestos waste in the plastic is between 60 and 80 percent by weight. 22. Encapsulated waste, characterized in that it is brought into a jacket (1) according to any of claims 7 to 18, which is surrounded by a reinforcing body (23). 23. Encapsulated waste, according to claim 22, characterized in that the waste is brought into said jacket (1) in loose form. 24. Encapsulated waste according to claim 22, characterized in that the waste in the jacket (1) is mixed with a thermoplastic so as to form a coherent solid mass.

Inventors: PINCKET ROGER, PINCKET, ROGER
Applicants: PINCKET ROGER, PINCKET, ROGER
Application year: 1994
Main classification: B09B3
IPC codes: B09B3, B28B23